1. Field of the Invention
This invention relates to a photographing apparatus having a trimming photographing mechanism, and particularly to a photographing apparatus having a trimming photographing mechanism of simple construction which is designed such that images of good quality (for example, photographs) are obtained in photographing operation having at least two modes, i.e., normal photographing (a first mode directed to a normal photographing area) and trimming photographing (a second mode directed to a photographing area narrower than the photographing area of the first mode) by appropriately setting the lens construction of a photo-taking optical system.
2. Related Background Art
A photographing apparatus having a trimming photographing mechanism which is designed such that one of normal photographing and trimming photographing is changed over by a changeover mechanism and photographing is effected with the then photographing mode and trimmed area recognized both from the outside of a camera and within a finder view field has heretofore been proposed in Japanese Laid-Open Patent Application No. 62-52541 and Japanese Laid-Open Patent Application No. 63-285524.
Also, Japanese Laid-Open Patent Application No. 54-26721 proposes a photographing apparatus (camera) capable of accomplishing so-called trimming information writing which comprises recording, on film, image information indicative of the enlargement range set during photographing.
Generally, in the photo-taking lens of a photographic camera, a video camera or the like, aberrations are corrected so that an optical performance of good balance may be obtained over the entire picture plane.
As the tendency of aberration correction in ordinary photo-taking lenses, the best image plane position indicative of curvature of image field is designed to incline toward the under-corrected (minus) side from the center of the photographing range (the optic axis) toward the marginal portion of the picture plane, thereafter return to the over-corrected (plus) side and lie on the more or less over-corrected (plus) side in the most marginal portion of the picture plane.
Thereby there is obtained an image of good quality which is well balanced over the entire picture plane. Design is also made such that when the ordinary enlargement of the entire picture plane is effected, there is obtained a good image (photograph) in which the deterioration of quality hardly weights on the photographer's mind.
There is a case where trimming is effected on an image, which is photographed by the use of a photo-taking lens of this kind, and an image of a photographing area (trimming area) narrow as compared with the ordinary photographing area is enlarged and printed.
In such case, in the most marginal portion of the picture plane of the image within the trimming area, the best image plane position greatly inclines toward the minus side and thus, the optical performance of the marginal portion of the picture plane is greatly reduced as compared with that of the central portion. This has led to the problem that the balance of the image quality of the entire trimming picture plane is greatly broken.
That is, there has been the problem that when an image is obtained by enlarging the trimming area in which aberrations are under-corrected over the entire picture plane, the deterioration of image quality becomes remarkable and the obtained image becomes a very unsightly image (photograph).